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Full text of "Model performance criteria for structural firefighters' helmets"

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U.S. DEPARTMENT OF 
COMMERCE 

NATIONAL FIRE 
PREVENTION & CONTROL 
ADMINISTRATION 

National Fire Safety and 
Research Office 



MODEL PERFORMANCE 
CRITERIA FOR 
STRUCTURAL 
FIREFIGHTERS' HELMETS 



August 1977 
Washington, D.C. 20230 



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MODEL PERFORMANCE 
CRITERIA FOR 
STRUCTURAL 
FIREFIGHTERS' HELMETS 



Prepared by; 

National Fire Safety and Research Office, 
National Fire Prevention and Control Administration 
U.S. Department of Commerce 
Washington, DC. 20230 



Based on Research Conducted by: 
Institute for Applied Technology 
National Bureau of Standards 
U.S. Department of Commerce 
Washington, DC. 20234 

August 1977 



Foreword 



Firefighting continues to be the Nation's most hazardous occupation. 
This report provides new information useful for improving one important 
part of a firefighters' protection, his helmet. 

Ultimately, a total protective system must be provided so that the 
firefighters' task will be effective, efficient and safe. Our Fire Services 
Technology program has this objective. 




Howard D. Tipton 
Administrator 



Table of Contents 



Page 

1 4 

Introduction 

1. Model Performance Requirements 5 

2. Associated Test Methods -^ 

3. Glossary of Terms 

4. Model Product Labeling ^3 

5. Appendix 

Bibliography ^^ 



Illustrations. 



17 



Model Performance Criteria for 
Structural Firefighters' Helmets 



Introduction 

The model performance criteria described in this document are 
intended to be used as the basis for developing and providing im- 
proved firefighters' helmets, particularly those used by fire 
departments that spend a significant amount of time fighting 
structural fires. Departments responsible for specialized 
firefighting functions including wildland and aircraft fires should 
use protective equipment specifically designed for those ac- 
tivities. Certain design features are specified which include ear 
flaps, chin strap retention, configuration and labeling require- 
ments. Provisions for face shields and other ancillary equipment 
are not part of the model requirements. 

The research effort leading to the preparation of this document 
v^/as conducted to present a set of performance requirements and 
associated test methods from which a standard specifically 
designed for structural firefighters helmets could be written. 

A supporting report titled: "Considerations in Establishing Perfor- 
mance Criteria for Structural Firefighters' Helmets" has been 
prepared to provide the background for this document and can 
be obtained by contacting the National Bureau of Standards, 
Department of Commerce, Washington, D.C. 20234. 



1. Model Performance 
Requirements 







,1 





1 . 1 Impact Attenuation 

When tested in accordance with paragraph 2.1, all 
helmets tested shall meet the requirements 
below: 



Impact 
Location 



Maximum 

Acceleration (m/sec/sec) 



Top 150 X gn *(1471.5 m/sec/sec) 

Front 400 x gn *(3924.0 m/sec/sec) 

Side 400 x gn *(3924.0 m/sec/sec) 

Back 400 X gn *(3924.0 m/sec/sec) 



Accelerations above 200 g^, shall not exceed three 
milliseconds in duration; accelerations above 150 
gn shall not exceed five milliseconds. 



1.2 Penetration Resistance 

There shall be no demonstrable electrical contact 
between the penetration test striker and the 
headform when the helmet is tested for penetra- 
tion resistance as described in paragraph 2.2. 

1.3 Chin Strap/Retention System 

The static strength of the chin strap/retention 
system shall be tested in accordance with 
paragraph 2.3 without any break occurring and 



*g„ denotes gravitational acceleration which is 
defined as 9.80665 meters per second. (See Ap- 
pendix) 



without any resulting slip or stretch of more than 
25 mm (1.0 in). The width of the chin strap shall be 
at least 12 mm (1/2 in). 



d) any shell distortion in the front and sides of 
the headform shall not extend more than 4 cm (1.6 
in) below the reference plane. 



1.4 Ear Flaps 

Ear flaps shall extend at least 25 mm (1 in) in front 
of the coronal plane and at least 60 mm (2.4 in) 
below the basic plane (see figure 2). 

Ear flaps shall resist ignition when tested in accor- 
dance with paragraph 2.4. 

1.5 ConHguration 

The helmet shall be designed to divert falling li- 
quids away from the face and neck. 

The helmet shall have no slits, holes or other 
openings above the reference plane (see figure 2). 
No part of the helmet shall extend more than 15 
cm (5.9 in) from the mid-sagittal plane (see figure 
1) nor more than 20 cm (7.9 in) from the coronal 
plane (see figure 2). Distances are measured 
perpendicular to the planes. 

1.6 Flame Resistance 

Helmet shells shall resist ignition when tested in 
accordance with paragraph 2.4. 

1.7 Heat Resistance 

when tested in accordance with paragraph 2.5: 

a) there shall be no visible distortion of the 
helmet suspension/retention system, chin strap, 
or ear flaps 

b) no part of the helmet shell shall touch the 
headform 

c) any shell distortion in the back of the head- 
form shall not extend more than 8 cm (3.1 in) 
below the basic plane, and 



1.8 Electrical Insulation 

Electrical leakage shall not exceed 3 milliamperes 
when the helmet is tested as described in 
paragraph 2.6. 

1.9 Visibility and Reflectivity 

1. For maximum visibility the helmet should be 
of minimum lightness in color such as white, 
yellow, light orange, light red, etc. For this 
document maximum visibility is designated as 
Munsell Value 7/(43.06%) for CIE source "C" 
(6774K) or lighter when tested in accordance 
with "Standard Method of Specifying Color 
by the Munsell System" or ASTM E308-66, 
"Standard Recommended Practice for 
Spectro-photometry and Description of Color 
in CIE 1931 System." 

2. The helmet shall have retro-reflective mark- 
ings on each of four locations; front, back, 
right side and left side. The area covered in 
each location shall be at least 40 cm- (6.2 in'). 
When tested as described in paragraph 2.7, 
the retro-reflective material shall meet the re- 
quirements given in the table below: 

Minimum Candlepower per 
Fool Candle per sq. Ft. 



Observation Angle 
(degrees) 


Entrance Angle (degrees) 




-4 


-1-30 -h50 


0.2 

0.5 


70 
30 


30 3.5 
15 3.0 



2. Associated Test Methods 




2. 1 Impact Attenuation Test 

Four helmets (for large purchases, suitable quality 
control procedures and sampling plans should be 
arranged. Mil Std. 105 "Sampling Procedures and 
Tables for Inspection by Attributes" is recom- 
mended as a guide) are required for the en- 
vironmental conditioning as described in 
paragraph 2.1.2. A schematic diagram of an impact 
attenuation test set-up is shown in figure 3. 

2.1.1 TEST EQUIPMENT 

2.1.1.1 Test Headform 

The test headform, which is size 7 1/4, shall con- 
form to the dimensions in figures 2 and 4. It shall 
exhibit no resonance frequencies below 3000 Hz; 
it may be made of any low resonance magnesium 
alloy such as magnesium K-1A. 

2.1.1.2 Drop Assembly 

The drop assembly consists of the test headform, 
the accelerometer, and the supporting crossarm 
assembly and shall have a total mass of 5.2 ± 0.2 kg 
(11.4 ± 0.4 lb). The center of mass of the assembly 
shall lie within a cone of 10 degrees included 
angle about the vertical, with apex at the point of 
impact. 

2.1.1.3 Test Anvil 

The test anvil shall be steel and have a flat striking 
surface. The anvil shall be firmly mounted on a 
steel plate 250X250X25 mm (10X10X1 in) 
minimum, backed with a solid mass of at least 140 
kg (309 lb). 

2.1.1.4 Acceleration Measurement System 

An accelerometer is used to measure the ac- 
celeration imparted to the helmeted headform 
upon striking the anvil and should be able to 
withstand shocks up to 2000gp|. The acceleration 
data channel, including all instrumentation which 
may alter the frequency content of the test data 
and all recording and analysis procedures, shall 



comply with SAE Recommended Practice J211b 
requirements for channel class 1000. The time 
duration of acceleration shall be measured to 
within +0.1 millisecond. 

2.1.1.5 Reference Anvil 

The reference anvil is substituted for the test anvil 
to check the acceleration measurement system. 
When the bare headform is dropped from an ap- 
propriate height, it shall produce a peak accelera- 
tion of 400 gp ± 20 gp and acceleration above 200 
gp, of at least one millisecond duration. The 
reference anvil may be of any material which will 
reproducibly yield these results. A reference anvil 
found to be suitable is a one-inch Open Blue 
Modular Elastomer Programmer available from 
MTS Systems Corp., P.O. Box 24012, Minneapolis, 
Minn. 55424. 

2.1.2 CONDITIONING FOR TESTING 

2.1.2.1 Room Temperature 

Condition one helmet at a temperature of 
20 - 28°C (68 - 82°F) for at least 4 hours. Test as 
in paragraph 2.1.3. 

2.1.2.2 Radiant Heat 

Condition a second helmet by exposing the 
helmet area to be impacted to an infra-red lamp. 
The area to be impacted is defined as the circle 
with 6 cm (2 3/8 in) radius with its center at the im- 
pact point of the helmet. Mount the helmet on 
the test headform in the appropriate drop posi- 
tion and raise the drop assembly to the prescribed 
drop height. Measure the radiant flux by tem- 
porarily removing the helmet from the headform 
and placing a radiometer in the impact area. Ad- 
just the distance of the heat source until a cons- 
tant radiant flux of 0.6 watts per square centimeter 
is achieved. Remove the radiometer and reposi- 
tion the helmet on the headform and subject the 
impact area to the radiant flux for three minutes. 

The heat source should be mounted so that it can 
be easily swung away to allow helmet impact im- 



mediately after the application of heat. Test ac- 
cording to paragraph 2.1.3. If the helmet is not im- 
pacted within 10 seconds after removal of the heat 
source, reapply the heat load for an additional 3 
minutes. 

2.1.2.3 Water 

Condition a third helmet by immersing it in water 
at a temperature of 25 ± 5°C ^1 ± Q^F) for not 
less than 4 hours nor more than 24 hours. Test ac- 
cording to paragraph 2.1.3 within 10 minutes after 
removal from the water. 

2.1.2.4 Low Temperature 

Condition a fourth helmet by exposing it to a 
temperature of -15 -I- -°2 C (5 -I- -4°F) for 
not less than 4 hours. Test according to paragraph 
2.1.3. If the test is not completed within one 
minute after removal from the cold temperature 
environment, recondition the helmet 10 minutes 
for each minute out of the chamber. 

2.1.3 TEST PROCEDURE 

Mount the accelerometer at the center of mass of 
the drop assembly with the sensitive axis aligned 
to within 5 degrees of the true vertical when the 
headform is in the impact position. 

Prior to testing, allow all electronic equipment to 
warm up for 30 minutes or until stability is 
achieved. Throughout calibration and testing, the 
ambient temperature shall be 20 to 28°C (68 to 
82°F) and the relative humidity 30 to 70 percent. 

Check all instrumentation before and after each 
continuous sequence of tests by impacting the 
bare instrumented headform on the reference an- 
vil. Record a minimum of three such impacts 
before and after a test sequence and make them 
part of the test record. Should the acceleration- 
time history not meet the required tolerance 
(2.1.1.5) prior to testing, adjust the equipment as 
necessary. Should the post-test average differ 
from the pretest average by more than 40 g^,, 
discard the entire test series. 



Position the helmet squarely on the headform and 
secure it to the headform-crossarm assembly by its 
chin strap or other means which will not interfere 
with the test, so as to maintain this position during 
guided fall. 

Adjust the drop height so that the velocity at im- 
pact is 6.0 ± 0.2 meters per second (19.6 ± 0.7 
ft/sec.) 

Impact each helmet once at each of the four sites 
described below: 



Drop 
Site 



Impact Area 



Top No more than 75 mm (3 in) from the point 

described by the intersection of the helmet 
sfiell, the mid-sagittal plane and the coronal 
plane (see fig. 2). 

Side No more than 75 mm (3 in) from the line 
described by the intersection of the coronal 
plane and the helmet surface, above the 
reference plane and below the top impact 
area. 

Front At least 25 mm (1.0 in) above the reference 
plane, below the top impact area and in front of 
the side impact area. 

Back Above the reference plane, below the top im- 
pact area and to the rear of the side impact area. 

The mass of the test helmet is not included in 
calculating the impact energy. 

2.2 Penetration Resistance Test 

Two of the helmets used in the impact attenuation 
test may be used for this test. A diagram of the 
penetration resistance test set-up is shown in 
figure 5. 

2.2.1 TEST EQUIPMENT 

2.2.1.1 Test Headform 

The test headform, which is size 7 1/4, shall con- 
form to the dimension in figures 2 and 4. Above 



the reference plane, it shall have an electrically 
conductive surface which is electrically connected 
to the contact indicator (2.2.1.3). 

2.2.1.2 Penetration Striker 

The penetration striker shall have a mass of 1.0 
kg -I- 25 g -0.0 g (2.2 lb + 0.05 lb - 0.0 lb). The 
point of the striker shall be a cone with an in- 
cluded angle of 60 ± 0.5 degrees, a height of 38 
mm (1.5 in) and a tip radius of 0.5 ± 0.1 mm 
(0.020 ± 0.004 in). The hardness of the striking tip 
shall be Rockwell scale-C 60, minimum. The 
penetration striker shall be electrically connected 
to the contact indicator (2.2.1.3). 

2.2.1.3 Contact Indicator 

The contact indicator shall indicate when 
electrical contact of 1 millisecond duration or 
longer has been made between the penetration 
striker and the conductive surface of the test 
headform. 

2.2.2 CONDITIONING FOR TESTING 



2.2.2.1 Room Temperature 

Condition one helmet at a temperature of 20 to 
28°C (68 to 82°F) for at least 4 hours. 

2.2.2.2 High Temperature 

Condition one helmet in a circulating air oven 
controlled at 100 + 3°C (212 ± 50°F) for not less 
than 4 hours nor more than 24 hours. 



2.2.3 TEST PROCEDURE 

Place the conditioned, complete helmet on the 
rigidly mounted test headform and secure it by its 
chin strap or by other means which will not in- 
terfere with the test. Adjust the helmet in the 
same manner as a person would adjust it to his 
head. Drop the penetration striker in guided free 
fall onto the outer surface of the helmet anywhere 
above the reference plane and at least 75 mm (3.0 



in) from the center of a previous impact site or 
penetration site. Drop the striker from a height of 
2.50 + 0.01-0 meters (98.5 + 0.4-0 in) as 
measured from the striker point to the point of 
impact on the outer surface of the helmet. Apply a 
minimum of two penetration blows at different 
locations to each of the two helmets. The long axis 
of the striker should be perpendicular to the 
plane tangent to the impact area. If the test is not 
completed within 3 minutes after high 
temperature conditioning, recondition and 
repeat. 

2.3 Chin Strap/Retention System Test 

The same test helmets used in the impact attenua- 
tion test may be used for this test. A diagram of 
the test set-up is shown in figure 6. 



2.3.1 TEST HEADFORM 

The test headform shall be size 7 1/4 and capable 
of supporting the helmet when a load of 890 
newtons (200 pounds force) is applied to the 
retention system. 

2.3.2 CONDITIONING FOR TESTING 

2.3.2.1 Room Temperature 

Condition one helmet at a temperature of 20 to 
28°C (68 to 82°F) for at least 4 hours. 

2.3.2.2 High Temperature 

Condition a second helmet by exposing it in a cir- 
culating air oven to a temperature of 100 + 3°C 
(212 + 5°F) for not less than 1 hour nor more than 
3 hours. 



2.3.3 TEST PROCEDURE 

Place the conditioned, complete helmet on the 
rigidly mounted test headform and fasten the chin 



strap to the loading device, as shown in figure 6. 
Adjust the helmet on the headform so that the 
points of attachment of the chin strap to the 
helmet will be subjected to the same stress as the 
chin strap. Support the helmet so that it will not ] 
move during the application of the test loads. ! 

I 
Apply the test loads perpendicular to the basic 
plane of the headform and symmetrically with 
respect to the helmet retention system. 

Statically load the chin strap system with 100 
newtons (22 pounds force) for at least 30 seconds 
but no more than 1 minute and then measure the 
maximum distance between the chin strap and 
the apex of the helmet. Do not remove the load. 

Apply an additional 550 newtons (124 pounds 
force) for at least 3 minutes and again measure the 
maximum distance between the chin strap and 
the apex of the helmet. 

Record any break in the chin strap/retention 
system. Record any slip or stretch as the dif- 
ference between the two distance measurements. 
If the test is not completed within 5 minutes after 
high temperature conditioning, recondition and 
repeat. 



2.4 Flame Resistance Test 

2.4.1 SHELL 

Place the helmet on an epoxy headform in front 
of a radiant heat source such as the type described 
in ASTM E162 so that the basic plane of the head 
form is parallel to the radiant heat source. Position 
the helmet so that the crown receives a radiant 
flux of 0.6 w/cm-. After 60 seconds exposure to 
the radiant flux, and without removing the helmet 
from the heat source, place the cone tip of a 
methane flame against the helmet crown so that 
the cone makes an angle of 45° with the plane 
tangent to the crown (see figure 7). After 15 se- 
conds remove the flame and observe whether the 
helmet shell resists ignition. (No visible flame or 



10 



afterglow 5 seconds after removal of methane 
flame.). If part of the shell is constructed of a dif- 
ferent material than the crown, test each material 
in an equivalent manner. 



2.4.2 EAR FLAPS 

The flame resistance test for ear flaps is the same 
as 2.4.1 with the following exceptions: 

1. The mid-sagittal plane of the helmet is parallel 
to the heat source. 

2. The ear flap receives a radiant heat flux of 0.6 
w/cm-. 

3. The cone of the flame is applied at an angle of 
45° with the ear flap. 



helmet. Apply a 60 Hz, alternating current voltage 
and increase it to 2,200 volts root mean square. 
Maintain the voltage at 2,200 ± 2% for 3 minutes 
(see figure 8). Caution should be exercised in con- 
ducting this test because of the high voltages re- 
quired. 

2.7 Visibility Test— Reflectivity 

The retro-reflective material shall be tested in ac- 
cordance with Federal Specification LS-300B 
paragraph 4.3.7 (Available from: Federal Supply 
Services, General Services Administration, 
Washington, D. C. 20407) 



2 . 5 Heat Resistance Test 

Mount the helmet with ear flaps down on an 
epoxy headform conforming to the dimensions in 
figures 2 and 4, and fasten the chin strap securely. 
Place the headform, with helmet attached, into a 
circulating air oven which has been preheated to 
250 ± 3°C (482 ± 5°F). After three minutes 
remove the helmet and headform and measure 
the shell distortion, relative to the basic and 
reference planes, at the front, sides and back of 
the helmet. Then remove the helmet from the 
headform and examine the chin strap, ear flaps, 
and retention system for distortion. 



2.6 Electrical Insulation Test 

Support the helmet in an inverted position with a 
wire frame and place it in a vessel containing tap 
water. Submerge the helmet until the water is 
within 13 mm (1/2 in) of the reference plane. Fill 
the inside of the helmet to within 13 mm (1/2 in) 
of the reference plane with tap water. Attach one 
terminal of a suitable transformer to the wire 
frame. ^ The second terminal is connected to an 
electrode and immersed in the water in the 



^The transformer should have an output voltage 
which is essentially sinusoidal with a crest factor of 
1.41 ± 0.07 (crest factor = peak voltage/true rms 
voltage). 



11 



3. Glossary of Terms 




3.1 Basic Plane 

The plane through the centers of the external ear 
openings and the lower edges of the eye sockets 
(see figure 1). 

3.2 Coronal Plane 

The plane, perpendicular to the basic and mid- 
sagittal planes, which passes through the centers 
of the external ear openings as modeled on a 
headform (see figures 1 and 2). 



3.3 Edging 

The edge, rim, or rim trim around a helmet. 

3.4 Headform 

A test device which conforms to the configuration 
of the human head (see figures 2 and 4). 

3.5 Mid-Sagittal Plane 

The plane, perpendicular to the basic and coronal 
planes, which symmetrically bisects the head (see 
figure 1). 

3.6 Reference Plane 

The plane 60 ± 1 mm (2.36 ± 0.04 in)' above and 
parallel to the basic plane. 

3.7 Retention System 

The complete assembly by which the helmet is 
retained in position on the head. 



3.8 Retro-Reflective Material 

A material which reflects and returns a relatively 
high proportion of light in a direction close to the 
direction from which it came. 



-Measures in parentheses are approximate. 
12 



4. Model Product Labeling 




Each helmet shall be durably and legibly labelled 
in a manner such that the label can be easily read 
without removing padding or any other perma- 
nent part. The label shall be affixed so that it is not 
easily removable and shall retain its integrity 
throughout the Associated Test Methods (Section 
2). Each label shall include the following informa- 
tion: 

(a) name or designation of manufacturer 

(b) model designation 

(c) size and weight' 

(d) month and year of manufacture (uncoded) 

(e) lot number 

(f) recommended cleaning agents, paints, etc., 
which can be applied to the helmet without 
damage 

(g) helmets which can be damaged by cleaning 
with common solvents shall include a warning 
that some common solvents may damage the shell 

(h) helmets with compressible linings shall in- 
clude a warning that after a severe blow the 
helmet may no longer protect the head and 
should be replaced or repaired by the manufac- 
turer. 



^Weight refers to the helmet, without accessories, 
as offered for sale. 



13 



5. Appendix 




Considering the lack of information on in vivo 
fiuman tolerance to head impacts, the variations 
in impact tolerance from person to person and 
between impact sites on the head, and that metal 
headforms used in the testing do not duplicate 
the response of the human head, it is obvious that 
the test methods in current use do not measure 
the actual protection provided by a helmet but 
rather the ability of a helmet to absorb the energy 
of a given impact. As test headforms become 
more realistic and more is learned about the 
tolerance of human heads to impacts, test 
methods will improve to the point where they ac- 
tually measure the amount of protection that a 
helmet affords in a given situation. In this country, 
there are basically two methods of testing protec- 
tive headgear: the falling headform/rigid anvil 
method described in ANSI Z90.1, and the falling 
ball/rigid headform method described in ANSI 
Z89.1 



Impact Attenuation 

The Z90 method requires impact tests to be con- 
ducted on all areas of the helmet top, front, sides 
and back; the Z89 method requires impact tests 
only in a small area on the top of the helmet. 
Although most of the impacts to firefighters may 
result from debris falling on the top of the head, it 
cannot be ignored that there is a danger of severe 
impacts to other parts of the head. Consider, for 
example, a firefighter crawling on a floor with his 
head down. It is very likely that falling objects will 
impact the back of his head rather than the top. 
There have been several reported cases of 
firefighters being struck on the sides of the head 
by errant hose nozzles. Clearly then, to be accep- 
table, a test method must be able to test all areas 
of a helmet for its ability to reduce the effects of 
impacts. 

This was an important consideration for selecting 
a method modeled on Z90 rather than Z89 to test 
fire helmets. 



14 



With the type of data obtained from the method 
described in Z90, there are several choices of 
pass/fail criteria: peak acceleration, severity index 
or head injury criteria. The peak acceleration 
described in Z90 is simply the maximum accelera- 
tion of the headform during impact. This is usually 
expressed in G's, the dimensionless ratio of the 
headform acceleration to the acceleration due to 
gravity (G = headform acceleration (m/sec-) 9.81 
m/sec'). 

A Severity Index is derived from the Wayne State 
University tolerance curve which shows that head 
injury is a function of time as well as acceleration. 
This is shown graphically in the Wayne State 
University Tolerance Curve below. 




10 5 15 20 25 30 35 40 45 
TIME-MILLISECONDS 



The Head Injury Criterion may be considered a 
refinement of the Severity Index. Both the 
Severity Index and Head Injury Criterion attempt 
to make maximum use of biomechanical informa- 
tion provided by the Wayne State University 
tolerance curve. Some standards such as DOT 218 
and the ANSI Z90 acknowledge the existence of 
the Wayne State University curve by including 
time limits as well as maximum accelerations in 
their acceptance criteria. Such considerations are 
included in the model performance criteria. 

The impact requirements in this document are 
based on test data obtained from various types of 
helmets and an assessment of the state-of-the-art 
in materials and helmet design. Helmets which 
meet the proposed requirements will substantially 
reduce the effects of blows to the head. In 1976, 
there were no fire helmets on the market that met 
these impact requirements (until now, all fire 
helmets have been patterned either after motor- 
cycle helmets fully lined with an energy absorbing 
material or industrial hard hats with sling suspen- 
sion systems). The current state-of-the-art in 
helmet design and manufacturing can be 
employed to produce fire helmets that provide 
better protection than either of the above 
designs. Moreover, the increased protection can 
be provided without an appreciable increase in 
cost and without sacrificing comfort. The require- 
ments in the model standard are based on this as- 
sumption. 

Penetration Resistance 

The penetration resistance test was developed by 
testing fire helmets with a penetrator similar to 
the one described in ANSI Z90. Leather, glass rein- 
forced plastic, and polycarbonate all have per- 
formed well in providing protection against 
penetration by sharp objects. For this reason, the 
requirements were set to prevent any lowering of 
present performance. 



15 



Bibliography 



Heat Resistance 

A frequently heard complaint about present 
helmets was low resistance to heat. To substan- 
tiate complaints, many deformed helmets and 
photographs of heat damaged helmets were 
presented by fire departments in different 
geographical locations. Using published reports, 
damaged helmets, photographs, discussions with 
users and laboratory test results as guides, the 
proposed thermal requirement was established as 
a reasonable test condition for high temperature 
performance. Under these conditions it is possible 
to duplicate damage to helmets that has occurred 
in actual use. 



Flammability 

These criteria require that the helmet and ear 
protectors be exposed to a direct flame and a high 
radiant heat load to insure that the protective 
headgear does not itself become a hazard if the 
wearer is exposed to an unusually hostile 
fireground situation. Several of the materials 
currently used for the fabrication of outer shells 
were tested and found to meet the proposed 
criteria. 



Chin Straps 

This requirement was proposed to prevent 
helmets from being dislodged during moderate 
impacts. Although chin straps can be made to 
withstand much greater loads, users expressed 
concern that neck injuries might result from un- 
yielding chin straps. These criteria allow manufac- 
turers to design chin straps that will break loose to 
avoid neck injury. 



Standard for Protective Headgear for 
Vehicular Users, ANSI Z90.1 1973 American 
National Standards Institute, Inc., 1430 
Broadway, New York, New York. 

Safety Requirements for Industrial Head 
Protection, ANSI Z89.1 American National 
Standards Institute, Inc., 1430 Broadway, New 
York, New York. 

Surface Flammability of Materials Using a 
Radiant Energy Source, ASTM E162, American 
Society for Testing and Materials, 1916 Race 
St., Philadelphia, Pa. 19103. 

Standard for Motorcycle Helmets, FMVSS No. 
218, National Highway Traffic Safety Ad- 
ministration, 400 Seventh Street, S.W., 
Washington, D.C. 

Standard for Riot Helmets, NILECJ STD 
0104.00, Department of Justice Law Enforce- 
ment Assistance Administration, 633 Indiana 
Avenue, N.W., Washington, D C 

D. L. Simms and P. L. Hinkley, "Protective 
Clothing Against Flames and Heat," British In- 
formation Services, 45 Rockefeller Plaza, New 
York, New York. 

SAE Recommended Practice J211b, Society of 
Automotive Engineers, Inc., Two Pennsylvania 
Plaza, New York, New York. 

Development of Criteria for Industrial and 
Firefighters' Head Protective Devices. HEW 
Publication No. (NIOSH) 75-125, January 1975. 



Electrical Resistance 

The requirement for electrical resistance is similar 
to ANSI Z89.1. Fire helmets that have met this re- 
quirement in the past have also performed 
satisfactorily in actual field use. 



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MID-SAGITTAL 
PLANE 




CORONAL 
PLANE 




Figure 1. Locations of basic, coronal, mid-sagittal and reference 
planes. 



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CJ ^ O- 








ro 

(D 
I 



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DROP FRAME 



BUSHING 




GUIDE - 
CABLES 



'zy\ 



BUSHINGS 

INSTRUMENTATION 
WIRE 



HEADFORM 
ACCELEROMETER 



ANVIL 



Figure 3. Impact attenuation test setup. 



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CO 





20 



GUIDE TUBE 



V 



R HELMET 



CONTACT 
INDICATOR 




Figure 5. Penetration resistance test setup. 



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HELMET 



HEADFORM 




RIGID RINGS 



LOAD 



Figure 6. Chin strap/retention system test setup. 



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Figure 7. Flame resistance test setup. 



23 



Q. 



<E^ 




00 

3 



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